Assessment of Urinary Osteopontin in Association with Podocyte for Early Predication of Nephropathy in Diabetic Patients

OBJECTIVES Microalbuminuria has been clinically used for noninvasive evaluation of renal dysfunctions. However, it is a nonspecific marker of diabetic nephropathy (DN). METHODS This study was conducted from March 2012 to April 2013 at Biochemistry Unit, King Fahd Medical Research Center (KFMRC). In this study, urinary osteopontin, podocytes number, and levels of immunoglobulin M (IgM) were determined in 60 patients (diabetic normoalbuminuria, diabetic microalbuminuria, and nephritic syndrome) compared with healthy subjects. RESULTS It was found that in diabetic microalbuminuria patients have a highly significant increase in urinary IgM, osteopontin, and podocyte levels as compared to other groups. Nephrotic syndrome patients showed a moderate significant elevation of these parameters compared to control subjects. At a given specificity of 97%, podocytes yielded the highest sensitivity of all markers, 95.5%. The sensitivity was considerably higher compared to IgM and osteopontin. Podocyte number was positively correlated with serum IgM and osteopontin (r = 0.63 and 0.56), respectively. Its cutoff corresponding to the 10% coefficient of variation was most appropriate for early diagnosis of DN. CONCLUSION Monitoring urinary podocyte may provide a noninvasive tool that is a sensitive, accurate, and specific biomarker of glomerular injury and can be used in combination with osteopontin and IgM to more reliably detect and monitor prognosis.